[13Psibies]

Take cash up front. Be professional about delivering. Make sure that the rate appropriately values all your weekends and evenings.

Keep your day job.

These guys don't know anything: having their $7000 developer "walk away" is a disaster and they think it's a feature.

What happens in the future is anyone's guess, but the mostly likely outcome is that nothing happens. The next most likely is that something modest happens. Etc. Many of the eventualities will require continued development; you're the first choice and you'll have the upper hand.